Method for treating tubular fabrics

ABSTRACT

A PROCESS FOR IMPREGNATING TUBULAR KNIT FABRICS WHICH INCLUDES THE STEPS OF CONTINUOUSLY ADVANCING THE KNITTED FABRIC HAVING A PREDETERMINED LOOP GEOMETRY, PASSING THE FABRIC IN A FLATTENED CONDITION BETWEEN A PAIR OF OPPOSED MOVING CONTACTING POROUS SURFACES TO SUPPORT AND MAINTAIN THE LOOP GEOMETRY OF THE FABRIC, ADVANCING THE PAIR OF POROUS SURFACES, WHILE PRESSING THE FABRIC, THROUGH A LIQUID TREATING BATH WHEREBY THE FABRIC IS IMPREGNATED WITH LIQUID WHILE THE LOOP GEOMETRY IS MAINTAINED WITHDRAWING THE FABRIC FROM THE BATH AND FROM BETWEEN THE POROUS SURFACES AND REMOVING THE EXCESS LIQUID FROM THE FABRIC, AS IT IS WITHDRAWN FROM THE BATH.

Nov. 28, 1972 E. I. ARONOFF METHOD FOR TREATING TUBULAR FABRICS 2. Sheets-Sheet 1 Filed March 30, 1970 INVENTOR Edward I. ARONOFF A TTORNE Y Nov. 28, 1972 E. I. ARONOFF METHOD FOR TREATING TUBULAR FABRICS 2 Sheets-Sheet 2 Filed March 30, 1970 wQ mg i ii... I!

INVENTOR Edwqrd l. ARONOFF .4 TTORNE Y i "United States Patent US. Cl. 117-7 7 Claims ABSTRACT OF THE DISCLOSURE A process for impregnating tubular knit fabrics which includes the steps of continuously advancing the knitted fabric having a predetermined loop geometry, passing the fabric in a flattened condition between a pair of opposed moving contacting porous surfaces to support and maintain the loop geometry of the fabric, advancing the pair of porous surfaces, while pressing the fabric, through a liquid treating bath whereby the fabric is impregnated with liquid while the loop geometry is maintained, withdrawing the fabric from the bath and from between the porous surfaces and removing the excess liquid from the fabric, as it is withdrawn from the bath.

The present invention relates to a process for treating knitted fabrics.

In the finishing of knitted fabrics to reduce shrinkage and stabilize the loops of the fabric, the fabric, the loops of which have been stretched longitudinally by washing and dyeing, is stretched laterally to reduce the longitudinal length of the loops, relaxed and then fixed. Such knitted fabrics are normally treated in a tubular form. In one stage of the process, particularly after the calendering or pressing stage, the tubular fabric is immersed in a resin bath to allow the resin to impregnate the threads of the fabric and thus further stabilize the loops thereof. Such a process is illustrated in British Pat. 952,681, Cohn et al., 1964.

Throughout the stages of the'finishing process preceding the resin-impregnation stage, care is taken to obtain the proper geometry of the loops of the fabric by reducing longitudinal tension and by attempting to at least regain the original width of the tubular fabric. However, as the fabric is fed into the bath of resin, the resin impregnating the threads immediately adds weight to the yarn of the fabric and causes the loops to contract, thus shrinking the fabric withwise. As the fabric is drawn from the resin-impregnation bath, it is then necessary to pass the tubular fabric over a stretcher frame in an attempt to regain the dimensions of the fabric obtained before entering the impregnation stage. Obviously, stretching widthwise the now stabilized resin-impregnated fabric, defeats the loop stability obtained by the resin impregnation.

An aim of the present invention is to provide a process and apparatus wherein the knitted fabric can be controlled dimensionally as it is being impregnated with resin.

A process in accordance with the present invention includes the steps of continuously advancing the knitted fabric at a predetermined yarn loop geometry, continuously immersing the fabric through a bath of resin suitable for impregnating and stabilizing the yarns forming the loops and simultaneously maintaining the loop geometry of the knitted fabric during the immersion thereof in the bath and thereafter by supporting the woven tube by a moving, porous support surface applying pressure to opposite sides of the woven tube so that excess resin drains but the woven tube loop geometry is retained during and after immersion in the resin.

Generally, an apparatus for the process includes a vessel suitable for containing a bath of liquid resin for im- 'ice pregnating the threads of the knitted fabric, means for maintaining the loop geometry of the knitted fabric while the fabric is passed through the confines of said vesssel, and means for removing excess liquid from the fabric as it comes out of the vessel. The means for maintaining the loop geometry of the fabric includes a pair of opposed fabric conveying means having endless surfaces adapted to continuously engage opposite surfaces of the fabric, under pressure, throughout the extent of the bath defined by the vessel, and means for driving said conveying means.

Having thus generally described the nature of the invention, particular reference will be made to the accompanying drawings illustrating a preferred embodiment thereof and in which:

FIG. 1 is a top plan view of the apparatus in accordance with the present invention;

FIG. 2 is a vertical longitudinal cross section taken generally along the lines II-II of FIG. 1;

FIG. 3 is a vertical cross section taken through line 33 of FIG. 2; and

FIG. 4 is a side elevation taken in cross section along a vertical plane of another embodiment of the present invention.

Referring now to the drawings, particularly FIGS. 1 and 2, the tubular fabric F is shown entering over a stretching device 10. The fabric which has been tensioned longitudinally in the various dyeing and washing processes, is then stretched widthwise so that the loops may regain their original shorter longitudinal length. Then the fabric is allowed to contract transversely so that the loops thereof have a width which is similar to the loops of predetermined size. The loops are then fixed by steaming the fabric with dry steam in a steam box 12 and then by pressing the fabric in the calender 14.

The fabric F enters into the next stage which is the impregnating stage indicated at '16. The apparatus comprising the resin irnpregnator 16 includes a housing 18, a vessel 20 adapted to contain a liquid resin solution R. The vessel 20 is mounted on supports 22 in the housing as shown in FIG. 2.

An idler roller 24 and a driven roller 26, preferably of rubber, are provided spaced apart from either longitudinal end of the vessel 20.

Below the vessel 20 is provided idler rollers 28 and 30. A conveyor belt or screen 25 passes over the driven roller 26 and the idlers 24, 30 and 28. Above the vessel 20 rollers 32 and 36 are provided which press against the previously described rollers 24 and 26. Idlers 34 and 38 are journalled in the housing and a conveyor belt or screen 35 is passed over the rollers 32, 34, 36 and 38. Roller 38 is located so that a portion thereof is in the vessel 20 as shown in FIG. 2 and is staggered from the plane defined by the nip of rollers 24, 32 and 26, 36 in such a way that the screens 25 and 35 will press against each other throughout the portion of the run thereof which passes through the vessel 20. The rollers 26 and 36 are particularly adapted to press against each other under pressure so as to remove the excess liquid from the fabric as it comes out of the impregnation stage 16. Roller 36, for instance, is rotatably mounted on a shaft 40 which in turn is slidably mounted in guide brackets on each side of housing 18. Hydraulic cylinders 42 are provided at each end of shaft 40 whereby, when the cylinders are actuated, the pistons 44 press the shaft 40 downwardly in the guide brackets so that the roller 36 presses against roller 26.

A drive motor M is provided which drives the roller 26 by means of a main drive about a suitable sprocket on the end of the shaft carrying the roller 26. The driven roller 26 passes the rotation of all the other rollers by means of the screens 25 and 35, particularly since there is surface contact between the rollers 26 and 36 beyond the edges of the fabric as it is being passed between the screens 25 and 35 between the rollers 26 and 36. This is shown more clearly in FIG. 4.

Further, nip rollers 46 and 48 are provided downstream of the rollers 26 and 36 whereby roller 48 is also adapted to move relative to the roller 46 under pressure. A drip pan 50 is provided underneath the rollers 46 and 48 to collect the excess liquid which is being extracted from the fabric F as it passes through the pressure rollers 46 and 48. A drain pipe 52 returns the liquid collected in the drip pan 50 to the vessel 20. Further rollers can be provided for further removing the liquid from the fabric after it is moved from the impregnation stage.

The fabric F which has been finished and calendered through the calender rolls 14 passes continuously between the rollers 24 and 32 and is held by the pressure of the conveyor screens 25 and 35 acting against opposite faces of the fabric F. The fabric F is passed through the impregnation bath between the conveyor screens which press on each side of the fabric and maintain the fabric under such control until the fabric passes by the press rollers 26 and 36. In this way, constant pressure is applied against the upper and lower faces of the continuous fabric, thus preventing the fabric from sagging in the bath. The screens 25 and 35 should be of suitable mesh to allow proper impregnation of the resin into the fabric and the vessel 20 can be increased in size, particularly in length, to suit the degree of impregnation required.

The rollers 26 and 36 should be of suitable soft rubber so that when they are pressed together, the conveyor screens 25 and 35 will press inwardly of the rubber rollers so as to reduce the damage which can be made on the knitted tubular fabric as it passes between the press rollers.

The screens 25 and 35 are made in an endless belt form and are preferably of metallic wire construction, but can be of other materials of similar properties.

Referring now to FIG. 4 of the drawings, another embodiment of the present invention is shown in which the fabric F which is drawn from the steam and calendering apparatus 112 and 114, into the impregnation stage 116 of a guide roller 118. The impregnation stage comprises generally a deep vessel 120 having side walls 122. A large hollow drum 124 is provided and is mounted on a driven shaft 126. Preferably, the hollow drum is of perforated metallic cylinder construction. The drum 124 is fixed to the shaft 126 which is in turn journalled to the side walls of the housing or vessel 120. Rollers 128, 130, 132, 134 and 136 are located about the vessel as shown in FIG. 4 and an endless conveyor screen 140 passes about these idler rollers. As can be seen from the drawing, a portion of the endless screen is actually in pressure contact with a portion of the surface of the drum 124, which is in the vessel 120. A further pressure actuated roller of soft rubber construction 142 is provided near the exit of the vessel 1120 and is adapted to press against the drum 124.

The fabric F passes over the guide roller 118 downwardly between the screen 125 and is pressed against the surface of the drum 124 as it passes through the resin or treating solution R. The dimensional stability of the fabric is thereby retained as it is pressed between the screen 125 and the drum 124. At the exit of the vessel 120, the fabric F continues on the surface of the drum 124 and passes over the press roller 142 while the screen 125 begins its return run over the roller 134. Most of the excess liquid is squeezed out of the fabric between the press roller 142 and the drum 124. However, adjacent the roller 142 is a pair of press rollers 144 and 146 which removes any excess liquid left in the fabric. Below the rollers 144 and 146 is a drip pan 148 adapted to collect the liquid extracted from the fabric between the rollers 144 and 146 and a return pipe 150 conducts the collected liquid back to the vessel 120.

I claim:

1. A process for impregnating tubular knit fabrics which includes the steps of continuously advancing the knitted fabric having a predetermined loop geometry, continuously passing the tubular fabric in a flattened condition between a pair of opposed moving contacting porous sur-- faces to support and maintain the loop geometry of the fabric, advancing the pair of opposed moving contacting porous surfaces, while pressing the fabric, through a liqid-treating bath whereby the fabric is impregnated by the liquid while the loop geometry is maintained, withdrawing the fabric from the bath and from between the contacting surfaces and removing the excess liquid from the fabric, as it is withdrawn from the bath.

2. A process as defined in claim 1, wherein the fabric is steamed and calendered before being immersed.

3. The process as claimed in claim 1 including maintaining said tubular fabric in a generally horizontal plane of movement together with the moving porous surfaces so that the liquid resin used to treat the tubular fabric will stabilize the loop geometry of the knitted fabric and prevent sagging of the tube until such stabilization is achieved.

4. The process as set forth in claim 3 including the step of forming the pair of moving contacting porous surfaces as juxtaposed runs of endless belts which intermediately dip into a resin treatment bath.

5. The process as set forth in claim 4 including the step of applying a predetermined pressure downstream of the treatment bath by means of power-operated nip rollers and salvaging excess resin and redirecting it to the resin treatment bath.

6. The process as set forth in claim 3 including the step of forming the pair of moving contacting porous surfaces as the run of an endless belt and a porous cylinder, and wrapping the run of the endless belt about a substantial portion of the outer surface of said porous cylinder' and moving the flattened tubular fabric therebetween.

7. The process as claimed in claim 6 including the step of applying a predetermined pressure downstream of the treatment bath and salvaging excess resin and redirecting it to the resin treatment bath.

References Cited UNITED STATES PATENTS 2,647,296 8/1953 Shive 117-115 2,647,488 8/1953 Shive 117-115 2,880,114 3/1959 Cohn et a] 26-55 R 3,175,272 3/1965 Cohn et a1 26-55 R 3,207,616 9/ 1965 Cohn et a1 26-55 R 3,402,059 9/1968 Cohn et al. 1177 3,484,949 12/ 1969 Aronoff 2655 R WILLIAM D. MARTIN, Primary Examiner M. SOFOCLEOUS, Assistant Examiner U.S. Cl. X.R.

117 47 R, 98, 99, 102 A, 26-55 R, 2873; 118-- 419,426 

